000
AXPZ20 KNHC 141510
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC SUN APR 14 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1330 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...             
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N77W TO 06N95W. THE 
ITCZ AXIS WAS ANALYZED FROM 06N95W TO 05N105W THEN CONTINUES 
FROM 06N115W TO 07N125W TO 04N1490W. SCATTERED MODERATE 
CONVECTION WAS WITHIN 180 NM S OF THE AXIS E OF 80W. NUMEROUS 
MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM N AND 120 NM S 
OF THE AXIS BETWEEN 81W AND 87W. A TROUGH BISECTS THE ITCZ FROM 
11N109W TO 07N110W TO 03N109W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION WAS WITHIN 90 NM W AND 210 NM E OF THE TROUGH 
FROM 03N TO 09N.

...DISCUSSION...                                                
A TROUGH ALOFT EXTENDS FROM AN UPPER LOW JUST E OF THE GALAPAGOS 
ISLANDS TO 14N107W. ZONAL WESTERLY FLOW DOMINATES THE AREA W OF 
THE TROUGH. THIS FLOW BEGINS TO DIVERGE AROUND THE TROUGH E OF 
115W WHICH IS ENHANCING THE VERTICAL MOTION FROM THE ITCZ TO 10N 
ALONG 110W WHERE A POOL OF 2.0-2.5 INCH PRECIPITABLE WATER 
VALUES LIES. SCATTERED MODERATE TO STRONG CONVECTION IS EVIDENT 
ON INFRARED IMAGERY AND IN LIGHTNING DATA NEAR THE 
AFOREMENTIONED SURFACE TROUGH THAT BISECTS THE ITCZ. THIS 
CONVECTION IS DESCRIBED IN THE SECTION ABOVE. UPPER DIFFLUENCE 
ASSOCIATED WITH A RIDGE AXIS THAT EXTENDS THROUGH NICARAGUA TO 
10N96W IS ALSO ENHANCING LIFT NEAR AN AREA OF POOLED LOW- TO MID-
LEVEL MOISTURE S OF THE MONSOON TROUGH OVER WATERS BETWEEN 81W 
AND 87W. TO THE N...THE MEAN UPPER TROUGH OVER THE SW U.S. AND 
NW MEXICO IS BEING RELOADED WITH NORTHERN STREAM ENERGY...WITH A 
STRONGER SHORTWAVE SYSTEM EXPECTED TO AMPLIFY THE TROUGH 
SIGNIFICANTLY STARTING MON. MEANWHILE...AN UPPER LOW NEAR 
27N144W WILL LINGER JUST W OF THE AREA WITH LITTLE FANFARE 
THROUGH THE FORECAST PERIOD. 

THE 1028 MB SUBTROPICAL SURFACE HIGH LIES NEAR 37N139W AND 
EXTENDS A RIDGE SOUTHEASTWARD 16N110W. PRIMARILY MODERATE NE 
TRADE WINDS CAN BE FOUND W OF THE RIDGE AXIS. TO THE NE OF THE 
RIDGE AXIS LIES A BROAD AREA OF N-NW WINDS TO GALE FORCE OFF THE 
COAST OF SOUTHERN CALIFORNIA N OF THE FORECAST AREA. THE 0604 
UTC ASCAT PASS SAMPLED THE WESTERN EDGE OF THIS AREA. N SWELL IS 
PROPAGATING FROM THIS REGION INTO NE FORECAST WATERS...WITH SEAS 
TO 8 FT FOUND FROM 27N-30N BETWEEN 120W-130W. THE SUBTROPICAL 
HIGH IS FORECAST TO MIGRATE NORTHWARD MON. IT WILL BE IMPINGED 
UPON BY A COLD FRONT TO ITS N TONIGHT...WITH HIGH PRESSURE 
REORGANIZING N OF THE FRONT. TRADES WILL REMAIN WEAK WITH THE 
HIGH WELL N OF THE AREA...BUT THE PRESSURE GRADIENT BETWEEN THE 
HIGH AND LOWER PRES OVER THE INTERMOUNTAIN WESTERN U.S. ...THAT 
IS EXPECTED TO DEEPEN AS THE DEEP-LAYER TROUGH AMPLIFIES...WILL 
KEEP GALE FORCE WINDS ALONG THE CALIFORNIA COAST THROUGH THE END 
OF THE PERIOD ON TUE. NORTHERLY SWELL WILL CONTINUE TO PROPAGATE 
INTO NE FORECAST WATERS...WITH SEAS EXPECTED TO BUILD AS HIGH 
AS 12 FT ON MON.

CROSS-EQUATORIAL SWELL WITH PERIODS IN EXCESS OF 20 SECONDS ON 
ITS LEADING EDGE HAS MADE ITS WAY TO THE ENTIRE CENTRAL AMERICAN 
AND MAINLAND MEXICAN COAST AS WELL AS THE BAJA CALIFORNIA 
PENINSULA S OF 26N. THIS SWELL WILL CONTINUE TO STRETCH N ALONG 
THE BAJA CALIFORNIA PENINSULA OVERNIGHT TONIGHT WHILE DAMPENING 
ALONG THE REMINDER OF THE COASTLINE. SEAS OVER 8 FT ARE 
CONFINED W OF THE GALAPAGOS S OF 09N BETWEEN 92W-115W AND E OF 
THE GALAPAGOS S OF 07N BETWEEN 80W-89W AS SEEN BY THE 0716 UTC 
JASON-2 AND 0720 UTC JASON-1 PASSES. THESE SEAS WILL GRADUALLY 
SUBSIDE BELOW 8 FT THROUGH MID-MORNING MON. 

$$
SCHAUER